ML20126A279

Submits Results of Westinghouse Reassessment of SG Tube Fatigue Evaluation in Response to NRC Bulletin 88-002. Actions to Resolve Peaking Ratios Issues Acceptable.Action on Bulletin Complete

ML20126A279
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	12/14/1992
From:	Shiraki C Office of Nuclear Reactor Regulation
To:	Kovach T COMMONWEALTH EDISON CO.
References
IEB-88-002, IEB-88-2, TAC-M67332, NUDOCS 9212180113
Download: ML20126A279 (3)

Text

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, December 14, 1992 J -

-Docket No. 50-295 Pr. Thomas J. Kovach Nuclear Licensing Manager Commonwealth Edison Company-Suite 300 OPUS West III 1400 OPUS Place Downers Grove, Illinois 60515

SUBJECT:

WESilNGHOUSE REASSESSMENT OF NRC. BULLETIN 88-02 FOR ZION STATION, UNIT 1 (TAC N0/467332)

Zion Station Unit I was identified by Westinghouse as one of the plants tequirita an update of the steam generator tube fatigue evaluations performed by Westir.ghouse in response to NRC Bulletin 88-02. The update was required as a result of NRC staff concerns regarding the accuracy of the antivibration bar insertion depth estimates and the associated flow peaking factor estimates.

Your letter of October 15, 1992 provided the reassessment which concluded that no tubes have peiking ratios large enough to cause the stress ratio to be greater than unity and, therefore, are not expected to be susceptible to high-cycle fatigue rupture at the top tube support plate in a manner similar to the rupture which occurred at North Anna (;ait No.-1.

The staff concludes that your actions resolve the issues identified in Bulletin 88-02 and are, therefore, acceptable. This finding' is subject to the development of administrative controls by you to ensure that updated stress ratio and fatigue usage calculations are performed in the event of any significant changes to the steam generator operating parameters (e.g., steam-pressure and flow, circulation ratio) relative to those assumed in the WCAP-analysis. Implementation of the additional administrative controls may be.

subject to verification by an NRC staff inspection. If, for any reason, you L

__do not plan to implement such administrative controls, please advise us within 30 days of receipt of this letter.

v our facility is no longer subject to the enhanced primary-torsecondary leak rate monitoring program required by item C.1 of the bulletin. This completes our action on this issue and closes.1AC No. 67332.

Sincerely, Original digncuIsy; 1700B0 Clyde Y. Shiraki, Sr. Project Manager ~

Project Directorate III-2 Division of Reactor Projects - III/IV/V

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, December 14, 1992 DocketNo.$0-295 Mr. Thomas J. Kovach Nuclear Licensing Manager Commonwealth Edison Company-Suite 300 OPUS West 111 1400 OPUS P1 ace Downers Grove, Illinois 60515

SUBJECT:

WESTINGHOUSE REASSESSMENT OF NRC BULLETIN 88-02 FOR ZION STATION, UNIT 1 (TAC NO.$67332)

Zion Station Unit I was identified by Westinghouse as one of the plants -

requiring an update of the steam generator tube fatigue evaluations performed by Westinghouse in response to NRC Bulletin 88-02. The update was required as a result of NRC staff concerns regarding the accuracy of the antivibration bar sertion depth estimates and the associated flow pr aking factor estimates.

Your letter of October 15, 1992 provided the reassessment which concluded that no tubes have peaking ratios large - gh to cause the stress ratio to be greater than unity and, therefore, are not expected to be susceptible to high-

, cycle f atigue rupture at the top tube support plate in a manner similar to the rupture which occurred it North Anna Unit No. 1.

The staff concludes that your actions resolve the issues identified in Bulletin 88-02 and are, therefore, acceptable. This finding is subject to the development of administrative controls by you to ensure that updated stress ratio and fatigue usage calculations are performed in the event of any significant changes to the steam generator operating parameters (e.g., steam pressure and flow, circulation ratio) relative to those assumed in the WCAP analysis. Implementation of the additional administrative controls may be subject to verification by an NRC staff inspection. If, for any reason, you ~

do not plan ', implement such administrative controls, please advise us within 30 days of receipt of this letter.

Your facility is no longer subject to the enhanced primary-to-secondary leak rate monitoring proo' a required by item C.) of the bulletin. This completes our action on this issue and closes TAC No. 67332.

Sincerely, Orig!nat Signed by, Clyde Y. Shiraki, Sr. Project Manager Project Directorate 111-2 Division of Reactor Projects - Ill/IV/V Office of Nuclear Reactor Regulation cc: See next page DISTRIBUTION Docket File NRC & Local PDRs JRoe TKing CMoore CShiraki JStrosnider FWilliams HConrad JDyer 0GC EJordan ACRS(10) PD32 r/f PD32 p/f EGreenman, Rlll

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' ) Mr. ' Thomas J. Kovach Zion Nuclear Power Station Commonwealth Edison Company Unit No. I cc:

Michael 1. Miller Esquire S;dley and Austin One first National Plaza Chicago, Illinois 60690 Dr. Cecil Lue-Hing Director of Research and Development Metropolitan Sanitary District of Greater Chicago 100 East Erie Street i Chicago, Illinois 60611 Phillip Steptoe, Esquire Sidley and Austin one First National Plaza Chicago, Illinois 60603 Mayor of Zion Zion, Illinois 60099 1111nois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 U. S. Nuclear Regulatory Commission Resident inspectors Office 105 Shiloh Blvd, Zior, Illinois 60099 -

Regional Administrator, Region 111 U. S. Nuclear Regulatory Commission 799 Poosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Off.ce of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, 11'inois 60601 5

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